Supernova 1987A, III

This sequence of images from Hubble Space Telescope follows the progress of Supernova 1987A, an exploding star discovered in February 1987. Radiation and debris from the explosion rammed into a cloud of gas and dust that the star had expelled before its death, forming a glowing ring with embedded knots of denser material. These images trace the evolution of that structure, as well as the glowing central cloud of debris, which expands considerably during the nine-year span of these images. [NASA/P. Challis/R. Kirshner (Harvard-Smithsonian Center for Astrophysics)/B. Sugerman (STScI)]

Supernova 1987A is one of the most photogenic objects in the universe. It looks like a bright pearl necklace flanked by two bright rings, all surrounding a central blob of light.

In fact, astronomers have been regularly snapping its picture since the supernova flared into view 25 years ago. The portraits not only show what 1987A looks like now, they help astronomers piece together a picture of the star's history.

The supernova was born when the core of a supergiant star collapsed, triggering a shockwave that blasted the star's outer layers to cosmic dust. Radiation from the blast lit up the rings. And the shockwave from the explosion itself has caused them to brighten even more.

One idea says the rings were born about 20,000 years before the explosion, when a second star merged with the supergiant. As the second star spiraled in, it helped spin off the outer rings. The merger caused the supergiant to spin faster, throwing off the material that formed the strand of pearls. But astronomers aren't sure why the inner ring looks like a strand of pearls instead of a smooth ring.

Debris from the explosion fills the space inside the rings. A shockwave reflecting off the rings is causing that material to glow more brightly. That's helping astronomers determine what elements the debris contains. And that reveals details about the original star and the explosion that blasted it apart, creating an astronomical beauty.

Script by Damond Benningfield, Copyright 2011

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